Chapter 20: Section 2 Advances in Science and Medicine What progress was made in the area of biological sciences? How did advances in medicine benefit society? What advances were made in the study of atomic theory?

Cell Theory in Biology Biological sciences (biology and genetics): sciences that deal with living organisms as does medicine. Physical sciences: sciences that deal with the properties of energy and nonliving matter. (ex. Astronomy, geology, physics, and chemistry) In the 1600s, scientists knew about the cell of the plants and animals (living matter) and notices that the cells of different species are of different shapes and sizes.

Rudolf Virchow A German scientist that discovered in 1850 that the cell is the basic unit of living matter. He showed that disease in living organisms was caused by changes in the cell or their destruction as a result of some outside force or agent. He also concluded that every new cell must come from some older cell and that only living matter can produce living matter.

Jean-Baptiste Lamarck’s Theory of Inheritance People believed that all the different kinds of plants and animals had been created at one time by divine beings. One group of scientist offered a different theory that argued that the thousands of kinds of modern plants and animals had evolved or developed from common ancestors long ago. This kind of development through change is called evolution.

The French biologist suggested that living things changed their form in response to their environment. Ex. A giraffe. Such changes were then passed on by inheritance to its descendants. Consequently other characteristics might gradually disappear if they were never used. Lamarck thought that these kinds of change continuing from generation to generation for millions of years could have produced present- day plants and animals out of the first bits of living matter. His theory did not become part of modern biology because it was later largely disapproved.

Charles Darwin’s Theory of Evolution He spent 30 years studying plant and animal life. In 1859, he published his theory of evolution in a book called On the Origins of Species by Means of Natural Selection. He began with a well-known biological fact: no two creatures are exactly alike, not even offspring and their parents. He combined this fact with Malthus idea that there were always more creatures born than could survive.

Therefore, Darwin said that: in any generation some creatures will survive and some will perish. Those who survive will be those whose characteristics are best adapted to the existing environment (the Survival of the Fittest /or Natural Selection) The strongest survivors will live to produce offspring, who will then repeat the process and tend to possess the advantageous traits of their parents. Darwin’s theory inspired a great deal of scientific activity. However, the theory of natural selection was controversial: 1. it stated that humans developed from animals. 2. it contradicted the story told by the holy book, religion.

Genetics: Gregor Mendel Darwin left an unanswered question (why were the offspring not exactly like their parents?) Mendel, a monk in Austria(1850,60), examined certain traits in plants and came to the conclusion that: inborn characteristics were not necessarily blended or mixed together. Instead, they were all inherited as if they were separate particles. A trait could be carried but not expressed. Mendel founded genetics: the study of the ways in which the inborn characteristics of plants and animals are inherited by their descendants.

The fight against disease: Jenner / Pasteur 1800s, 50% of the people born died within the first 5 years. Edward Jenner (an English physician) found a way to protect against smallpox. He used the principle of inoculation (an old Indian technique), he made a vaccine from the fluid in cowpox sores and scratched it into the skin of a boy’s arm.

Louis Pasteur (a French Chemist) identified small microorganisms called bacteria. Until Pasteur’s time, scientists believed that certain living things, including bacteria, sprang to life out of nonliving matter (spontaneous generation). Pasteur proved otherwise, he learned that bacteria is responsible for fermentation. He then developed a process called pasteurization: a process of heating liquids to kill bacteria and prevent fermentation. He also determined that some bacteria cause diseases in animals and humans (harmful bacteria: germs or microbes)

1870, he examined with anthrax. He produced a vaccine containing weakened anthrax germs which he injected into animals. He discovered that when weakened germs enter the body, the system builds up substances called antibodies to fight them. He used the same technique to fight rabies.

The development of surgery People that went under the knife used to be sedated using opium and liquor. 1840s, it was discovered that ether and chloroform would cause unconsciousness. Joseph Lister, using Pasteur’s discoveries, developed antisepsis: the process of killing disease-causing germs. He used carbolic acid as an antiseptic.

Other medical advances Robert Koch (German physician) found the germ for tuberculosis, Asiatic cholera. Aspirin 1890 Insulin 1920 Sir Alexander Fleming of Great Britain discovered penicillin 1928

Atomic Theory People accepted the philosophy that all matter in the universe consists of very small particles called atoms. (although there was no experimental proof or mathematical demonstration that supported it) John Dalton (an English chemist and school teacher) was the first to have experimental data in He outlined a method of “weighing” atoms. Ex. Hydrogen , Dmitry Mendeleyev (a Russian chemist) produced the periodic table (classification of elements) Scientist then discovered that these atoms move faster and collide with each other in a hot substance.

The Structure of the Atom 1895, X rays. 1897, the electron: a tiny particle that has a negative electrical charge. That all atoms contained electrons. This made these particles the true building blocks of all matter in the universe. Pierre and Marie Curie (radioactivity) Rutherford discovered the protons.

Planck and Einstein Two German scientists made great discoveries: Max Plank: quantum theory: energy could be released in definite “packages”. Albert Einstein: special theory of relativity: no particles of mater can move faster than the speed of light.

Science Fiction Kepler’s book The Dream was considered by many as the first science fiction work.